<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>内联</title>
    <style>
        a:link {
            border: 5px solid blue;
        }

/*         p {
            line-height: 1em;
        } */
        big {
            font-size: 250%;
            line-height: 1em;
        }

        .outer{
            width: 400px;
            /* height: 400px; */ /* 若设置这个，由于bottom大于inner的20px,故看不出来*/
            background-color: gray;
            overflow: hidden; /* 解决溢出问题 */
        }

        .inner1 {
            width: 100px;
            height: 100px;
            background-color: orange;
            margin-top: 20px;
        }

        .inner2{
            width: 100px;
            height: 100px;
            background-color: green;
            margin-bottom: 20px; /* 又被它的父元素抢走了*/
        }
    </style>
</head>
<body>
    <p>
        Not only does this paragraph have "normal" text, but it also<br />
        contains a line in which <a>some big text</a> is found.<br />
        This large text helps illustrate our point.
      </p>

      <div class="outer">
        <div class="inner1"></div>
        <div class="inner2"></div>
      </div>
      <div>我是一段测试文字</div>
</body>
</html>